In a digital broadcast receiver that is mounted in a moving object and that receives a broadcast program and data service while moving together with the moving object, broadcast stations from which the digital broadcast receiver can receive programs change depending on the movement, and the digital broadcast receiver is not always in a state in which its reception state is stable at all times. For this reason, there has been provided a digital broadcast receiver that includes a sub tuner in addition to a main tuner, thereby searching for receivable programs by using the sub tuner, and updating a list of programs which can be watched or listened to. By using such a sub tuner, it becomes possible to, for example, during the reception of a program by the main tuner, select, in advance, a broadcast station providing the same program broadcast at a frequency different from that of the program, i.e., a so-called alternative program, seamlessly switch to the alternative program, and receive data service of one or more programs.
However, one sub tuner cannot perform plural operations simultaneously. For example, in order to receive data service of a program, it is necessary to continue selecting a corresponding broadcast station, and thus it is impossible to select another broadcast station in the meantime. Therefore, during the reception of data service, it is impossible to perform a broadcast program search and the channel selection of a broadcast station broadcasting an alternative program. More specifically, during the reception of data service, it is impossible to provide the user with an update in real time of the program list and seamless switching to an alternative program.
Therefore, it is desirable to implement an efficient broadcast program search, alternative station channel selection, and data service reception by controlling the performance of these operations of the sub tuner including the broadcast program search, the alternative station channel selection, and the data service reception in accordance with the state.
For example, Patent Literature 1 discloses a dual-tuner radio receiver in which, when the received field strength of a main tuner means a strong electric field, a sub tuner is used exclusively for Vehicle Information and Communication System (VICS, registered trademark/this description will be omitted hereafter) reception, when the strength means an intermediate electric field, the sub tuner performs time division processing of network follow reception and VICS reception, when the strength means a weak electric field, the sub tuner is used exclusively for network follow reception, and when the strength means a very weak electric field, the sub tuner is used exclusively for VICS reception.